The correct option is A 2
A typical weighing balance compares a known quantity of weight with an unknown weight.
In our case, the known weight is 11 units (right hand side) which is being balanced by the weight on the left hand side.
Let the weight of each brick be x units.
Weight on left hand side = 7+2x
Since the weighing scale is in balanced position the weight on both the sides must be same.
=>7 + 2x = 11
=> 2x = 11 - 7
=> 2x = 4
Therefore, x = 2
Hence, each brick weighs 2 units.